I. Field
The following description relates generally to communication systems, and more particularly to multichannel communication systems.
II. Background
In order to address the issue of increasing bandwidth requirements that are demanded for wireless communications systems, different schemes are being developed to allow multiple user terminals to communicate with a single access point by sharing the channel resources while achieving high data throughputs. Multiple Input or Multiple Output (MIMO) technology represents one such approach that has recently emerged as a popular technique for the next generation communication systems. MIMO technology has been adopted in several emerging wireless communications standards such as the Institute of Electrical Engineers (IEEE) 802.11 standard. IEEE 802.11 denotes a set of Wireless Local Area Network (WLAN) air interface standards developed by the IEEE 802.11 committee for short-range communications (e.g., tens of meters to a few hundred meters).
In a wireless network having multiple users, as the physical layer data rates increase, MAC protocol efficiency decreases due to associated overhead. One way to alleviate this problem is to perform time division multiplexing among the multiple users. This reduces the amount of overhead associated with certain common factors, such as preamble. Also, this reduces the overhead associated with the mandatory spacing that needs to be provided between different packet transmissions. When considering the unlicensed spectrum available for the 802.11 WLAN systems, there exists a large amount of available bandwidth for packet transmissions. Typically the bandwidth is split into different channels that are 20 MHz wide. If more than one single channel is free in a distribution system, better utilization of this resource will enable higher aggregate throughputs. Consequently, it would be desirable to address one or more of the deficiencies described above.